The present invention, in some embodiments thereof, relates to nanotechnology, and, more particularly but not exclusively, to multicomponent nanostructures, a process of preparing same and uses thereof.
To date, 1-D nanomaterials, especially high aspect ratio anisotropic structures like nanorods, nanowires, coaxial structures, and nanotubes, are widely prepared via a template-based method, which has been shown to be to be a straightforward synthetic route to this effect. The template-base method utilizes a template membrane, with a dense-pore geometry and monodisperse diameters with a narrow diameter distribution. Exemplary utilizable membranes are made of polycarbonate or anodized aluminum oxide (AAO).
The formation of metallic nanostructures within the template pores can be implemented either by chemical electroless reduction [23] or electrodeposition. Electroless deposition of an appropriate electrolytic bath inside the pores may be accomplished in a two-step process: initiation, and deposition. Deposition begins at the pore walls, creating hollow metal nanotubes within the pores at short deposition time, but as deposition time increases, the membrane pore fills and the nanotube becomes a nanorod. Alternatively, in electrochemical deposition, the material to be deposited into the template membrane must be both easily reduced and conductive, in order to form the required nanostructures. Depending on the sequential electrochemical synthesis method used, nanorods composed of metals, polymers, and semiconductors may be fabricated.
Nanostructures are formed using the template membrane via unidirectional growth, which allows varying the composition of the nanostructures in the axial direction, via, for example, sequential deposition. Such template-based building blocks offer exciting applications, such as, for example, nanorods consisting of 1 μm-long Pt and Au segments, which are able to move autonomously in aqueous hydrogen peroxide solutions by the catalytic formation of oxygen at the Pt end [17-19].
Multi-segmented nanorods of Au—CdS—Au and Au—Ppy-Au [20], which possess unique electronic properties for functioning as nanodiodes and nanoresistors, respectively, were also obtained by template-based method. The multiplexed detection and sensing of biological analytes with the use of striped metallic nanorods known as Nanobarcodes [21] (NBs) were also achieved through sequential electrochemical deposition. Bifunctional Au/Ni nanorods were shown to be an effective tool in gene transfer [22].